Wide-scale declines in live coral cover have been observed throughout history. Modern day coral populations face a multitude of environmental disturbances, however one of the most devastating to the reefs in the Indo-Pacific is the crown-of-thorns starfish (Acanthaster planci), which feeds on the tissues of live corals. The rate at which these individuals feed combined with the explosion of populations in times of outbreak have been seen to exert some of the biggest pressures on coral reefs to date. Following recent episodes of crown-of-thorns starfish (COTS) outbreaks, research on the organism has become increasingly prevalent on the scientific agenda. The following study was conducted to assess the reproductive output of COTS with and without naturally damaged arms to further analyze the role of predation on the population dynamics of this species. Images of histological slides were utilized in doing so, allowing the egg sizes of individuals with damaged arms to be compared with the egg sizes of those with fully intact arms. Overall, it was found that while there was no noticeable trend between size of the COT individual and their respective egg sizes and the severity of injury that the individual experienced and the eggs they produced, however it appears there is a correlation between the individual’s overall state of health and their reproductive output. In short, fully intact individuals produced larger eggs than those that were predated upon; however, in looking closely at the data collected from four specific individuals (two being fully intact and the other two being injured), it became clear that this trend does not always hold true. Therefore, it is possible that other factors confounded the results of this study, and these are specifically outlined. Future research may include examining the effect of predation on the abundance of eggs produced, as this study focused solely on measuring egg size.
Animal Sciences | Environmental Sciences | Life Sciences | Marine Biology | Oceanography | Terrestrial and Aquatic Ecology
Mucha, Emily, "The effects of sub-lethal predation on the reproductive output of Acanthaster planci (crown-of-thorns starfish)" (2016). Independent Study Project (ISP) Collection. 2427.